270 likes | 423 Views
Winter Flounder Stock Enhancement: Examining the Onset of Wild Weaning in Pellet-Reared Fish. Stacy Farina, Michelle L. Walsh, and W. H. Howell The Department of Biological Sciences University of New Hampshire, Durham, NH 03801. A Little About Myself.
E N D
Winter Flounder Stock Enhancement: Examining the Onset of Wild Weaning in Pellet-Reared Fish Stacy Farina, Michelle L. Walsh, and W. H. Howell The Department of Biological Sciences University of New Hampshire, Durham, NH 03801
Science Consortium for Ocean Replenishment (SCORE) • Enhancement of natural marine populations • Invertebrates and Fish • Sponsored by NOAA NMFS & NOAA Aquaculture • UNH: Winter Flounder http://www.stockenhancement.org
Why Winter Flounder? http://www.nefsc.noaa.gov/sos/spsyn/fldrs/winter/
Commercial Importance http://weblogs.baltimoresun.com/entertainment/dining/reviews/blog/WholeFlounder.jpg
Recreational Importance http://mordantorange.com/images/comics/animals/shinybait.gif
Why Winter Flounder? * * Gulf of Maine http://www.nefsc.noaa.gov/sos/spsyn/fldrs/winter/
Possible Solution:Stock Enhancement • Winter flounder vulnerable in early life stages • Spawn and raise fish in captivity • Release to enhance natural stocks • Problem: Weaning onto Wild Diets
Weaning? Transitioning to a wild diet once released
Winter Flounder Diet • Captivity • Formulated Pellets (most common) • inexpensive and easy • Wild • Live diet (worms, zooplankton, etc)
Why is weaning important? Transitioning to a live diet can be stressful! YIKES! http://www.nmfs.noaa.gov/fishwatch/species/winter_flounder.htm
Our Project Examine the transition of pellet-reared winter flounder onto a wild diet once released
Methods • Spring 2007 • Juvenile winter flounder reared in the Laboratory • Summer 2007 • Released in cages (10 fish per cage) in a cove • UNH’s Coastal Marine Laboratory • Cages were retrieved every 3 hours after release up to 51 hours
Mick Walsh and Laughlin Siceloff Nate Rennels
Methods • Fall 2007 – Summer 2008 • Fish dissected • Stomach contents were examined and quantified
Results and Discussion Get ready for some graphs! http://www.nmfs.noaa.gov/fishwatch/species/winter_flounder.htm
Onset of Feeding % Fish With Food in Stomach per Retrieval After 18 hours, the number of fish feeding was significantly higher than at 12 hours after release. (p < 0.05)
Diet Composition Most commonly selected prey: Polychaetes (48.2%) and Copepods (31.2%)
Polychaete Worms Copepods Nematodes Bivalves
Diet Composition • First 12 hours • Inorganics • (rocks)
Diet of Wild Fish (Katie Robertson) Values Based on IRI Calculations
What Can We Conclude? • After 18 hours, most fish had food in their stomachs. • Inorganics were common within the first 12 hours, but minimal after. • Diet was composed of mainly polychaete worms and crustaceans (copepods and amphipods), and was similar to that of wild fish. • Gut fullness increased with time.
Ongoing Work • Long-term studies of feeding, growth, and survival after release • Examine impact of live laboratory diets on onset and quality of weaning • Assess feeding behavior of winter flounder raised on formulated pellets
Acknowledgments We gratefully acknowledge Elizabeth A. Fairchild, Nate Rennels, Travis Ford and Laughlin Siceloff for their assistance with experimental design and field work, and Kristin Garabedian and Katie Robertson for help with dissections and data entry. We thank the laboratories of Jim Haney and Larry Harris for use of their equipment. This project was funded by the University of New Hampshire’s Hamel Center for Undergraduate Research, The Graduate School and the Science Consortium for Ocean Replenishment (SCORE), a division of the National Oceanic and Atmospheric Administration (NOAA).